Patent No. DE 35 37 314 A1 discloses an apparatus for interrupting current in which an electrical connection is disconnected by the explosion of an explosive charge. A tubular bridging contact composed of ductile material between a first and second electrode has notches internally as weak points, and has an explosive charge externally, inside a pressure chamber.
If the current to be monitored exceeds a current limit value which can be determined, the explosive charge is detonated. An arc produced in this case is blown by the mixed gas emerging from the pressure chamber, and is quenched at the next current zero crossing. A disadvantage in this case is that, apart from the explosive charge, the electrodes and the bridging contact also have to be replaced after each disconnection process. As a result of the arc, electro-negative gas is released, as a component of the mixed gas, from the lining of the inner wall of the pressure chamber, leading to consumption of the latter.
DE 19 613 568 A1 discloses a power breaker for operating voltages up to 30 kV, in which first and second electrodes are electrically conductively connected, when closed, by means of a moving, circular-cylindrical switching pin as a bridging contact. Between the electrodes, the switching pin is surrounded circumferentially by a pressure chamber. A rated current path, which is provided with moving rated current contacts, may be arranged in parallel with the power current path. When the power breaker is switched off, the rated current path is interrupted first of all, as a result of which the current commutates onto the power current path. Afterwards the power current path is interrupted. An arc is formed in the process, and is then quenched. The drive for the switching pin, which can reach a speed in the range of 10 m/s-20 m/s during switching, is not quoted in any more detail. The switching pin, which is connected to a relatively complex switching drive for a rated-current contact finger, is subjected to a high load during switching.